The cell phone is becoming a necessity in countries around the world. Common cell phone features include address books, day timers, clocks, answering machines and games. More recently, cell phones allow connection to the World Wide Web, email, text messaging and even making purchase transactional payments.
A cell phone also commonly employs a digital camera (a “camera phone”). Images taken by the camera phone are not, generally, for professional purposes but are, instead, taken for fun. Some of the more useful applications of the camera phone include the capture of a map or address from an advertisement or phonebook, and the capture of information from a new acquaintance's business card, for example.
Other new cell phone features are under development. For example, credit card companies seek to make plastic credit cards obsolete. Instead, a cell phone will store credit card information that is used to complete purchase transactions by an infrared (IR) or radio (e.g., BLUETOOTH®) communication link. Though convenient, this system can lead to significant monetary damage if the cell phone is misappropriated by persons who make unauthorized purchases.
Iris recognition technology is gaining acceptance in the biometrics industry. An iris is a unique feature of each human being; it may therefore be used to distinguish one person from another. An iris remains stable over almost the entire human lifetime, and, as an internal organ that is externally visible, it is both easily accessible and well protected from the environment. The variability in iris texture from one person to another is so great that it is virtually impossible for any two people to have the same pattern. By storing iris patterns in a database, for example, an iris image can be scored against each stored iris pattern; the score indicating the probability of a match between the image and the stored pattern.
Iris recognition technology may be combined with the digital camera in a cell phone to provide user identification and transactional security. Accordingly, credit card information stored on the cell phone may only be accessed after the user takes an image of his iris; the iris image is confirmed in the cell phone by matching the image to previously stored iris image information. Iris information can be stored in a physically separate card or stored within the cell phone. In addition, the cell phone may be locked such that, when the cell phone is turned on, the user must image his or her iris to match one or more previously stored iris signatures of users allowed to use the phone or the credit card information.
An iris recognition system may also be incorporated into a conventional digital still or video camera such that, if a feature such as “recognition required” is turned on, then the camera will not operate until the iris of an authorized user is recognized. Such a feature deters theft of the cell phone and of vital information stored within the device, especially if the camera is marked as so protected. Similarly, these security features may also be incorporated into personal digital assistants (PDAs) that include a digital camera.
One problem with iris recognition involves the user interface. An iris image must be of sufficient resolution to resolve texture within the iris. In digital cameras with detectors that have few pixels, the field of view is so small that significant skill is needed to align an eye with the camera. Good iris imaging also depends upon controlled illumination and, obviously, a willing subject. In certain iris imaging systems, the digital camera has zoom and focusing capabilities to capture the iris image with sufficient clarity and resolution. However, these zoom and focus capabilities increase cost and size of the digital camera; increased size being a particular disadvantage for use within a cell phone or PDA.
Turning now to the drawings, wherein like components are indicated by like reference numbers throughout the various figures, attention is immediately directed to FIG. 1 illustrating a prior art imaging device 12 that has traditional optics 14 and a detector 16. Imaging device 12 is, for example, a digital camera. Imaging device 12 is shown imaging an iris of an eye 18. Traditional optics 14 form a usable image 15 of eye 18 only when eye 18 is within a depth of field 13 of optics 14. Thus, the depth of recognition of imaging device 12 is very small, making imaging device 12 difficult to use.
FIG. 2 illustrates operation of imaging device 12 of FIG. 1 installed in a camera phone 20. A user 22 holds camera phone 20 at a precise distance from her eye 18 (i.e., such that eye 18 is within depth of field 13 of imaging device 12) to ensure that a good image is captured by imaging device 12. Camera phone 20 may, for example, also include iris recognition processor 26, such that camera phone 20 is not operational (i.e., locked) until iris recognition processor 26 validates a captured iris image of eye 18. Iris recognition processor 26 may store one or more iris patterns of authorized users of camera phone 20, such that the captured iris image is validated against stored iris patterns. A cell phone service provider may store these iris patterns remotely for added security. The cell phone service provider may also store the iris patterns of individuals who attempted to access the device, thus providing an added deterrent to theft. Iris recognition processor 26 creates an iris pattern from the captured iris image and sends this iris pattern to cell phone service provider for validation. If the iris pattern matches a stored pattern, as determined by either recognition processor 26 or the cell phone service provider, camera phone 20 is unlocked.
One method for facilitating the capture of a usable iris image is to determine when the camera is at the correct distance from the eye by using a distance-determining sensor on the digital camera. The distance-determining sensor may include a tone indication or a light to indicate when the eye is at the correct distance from the camera. However, the distance determining sensor adds complexity, size and cost to the camera phone. To make digital camera units more affordable, inexpensive lenses are often used. However, the inexpensive lenses may result in reduced imaging quality such that effective iris image capture may be difficult.